HWK UHX line is the cat`s pajamas when it comes to fluoro-free race wax! The UHX Blocks are a great top-coat for fast top speed and acceleration. Load the block onto half of a wool roto brush, apply to ski base with 2-3 passes, then buff with the clean half of your wool for another 2-3 passes. The UHX Mid Black is for dirty, dry to wet snow from -10C to 0C.